1. Field of the Invention
The present invention relates to a fuel cell powered vehicle that travels by using electric power generated by a fuel cell.
2. Description of the Related Art
Development of fuel cell powered vehicles has been underway. A fuel cell powered vehicle includes a fuel tank that stores hydrogen gas or any other suitable substance, a fuel cell stack (hereinafter simply referred to as a fuel cell) that generates electricity in a chemical reaction between fuel and air, more specifically, oxygen in air, a rechargeable battery, and an electric motor that drives a driven wheel.
Many conventional fuel cell systems for four-wheel vehicles generate a relatively large amount of electricity as much as several tens of kilowatts but also produce heat equivalent to the generated electricity. To address the problem, a conventional fuel cell system for a four-wheel vehicle includes a water cooling system having high cooling efficiency. To generate a large amount of electricity, a conventional fuel cell system for a four-wheel vehicle includes a compressor provided to deliver a large amount of air to the fuel cell system.
Fuel cell powered motorcycles as an example of the conventional fuel cell powered vehicle include a water-cooled fuel cell system capable of generating a relatively large amount of electricity. A fuel cell powered motorcycle of this type includes a fuel cell cooling radiator disposed at a front position in a vehicle body, a cooling system disposed behind the radiator and thermally connecting the radiator to a fuel cell and a variety of electric parts, the fuel cell disposed behind the cooling system and below the front end of a seat, and a fuel tank disposed behind the fuel cell and substantially occupying a space below the seat (see Japanese Patent Laid-Open No. 2008-213742, for example).
On the other hand, an air-cooled fuel cell system, which generates a relatively small amount of electricity, for example, several kilowatts, does not require a radiator, a cooling water pump, a reservoir tank, or a variety of pipes that form a cooling system in a water-cooled fuel cell system, and heat produced in association with electricity generation can be cooled by air used as a reaction gas. Further, in an air-cooled fuel cell system, pressure loss produced along an air passage is advantageously low. As a result, an air-cooled fuel cell system not only has a simple system configuration in which an auxiliary component is not necessarily a compressor but simply a blower fan but also can reduce electric power consumed by the auxiliary component. In view of the fact described above, an air-cooled fuel cell system is sometimes used in a fuel cell powered motorcycle that requires less power in traveling than that in a four-wheel vehicle and a fuel cell powered vehicle, such as an electric wheelchair and other small electric vehicles.
In a fuel cell powered vehicle, it is necessary to determine the positions where the fuel tank, the fuel cell, and the electric parts are mounted in consideration of safety of the fuel tank for storing hydrogen gas, which is fuel, performance in cooling the fuel cell and the variety of electric parts, leakage of the hydrogen gas, which is fuel, and other safety factors when troubles occur.
However, when a high priority is placed on the shape of the fuel cell powered vehicle determined in consideration of driver's maneuverability and a structure for securely protecting the fuel tank, the electric parts are inevitably disposed in scattered positions. In this case, wire routing between the electric parts is complicated and the length of the wiring increases accordingly, resulting in increase in weight of the fuel cell powered vehicle and hence inefficient use of the output from the fuel cell. Further, in the process of cooling the fuel cell and a variety of electric parts, the flow of coolant is complicated, resulting in inefficient cooling and difficulty in controlling the flow of the coolant.